Many different types of instrument support mechanisms exist in the medical industry for supporting medical instrumentation in front of a patient. Often, the patient is seated in an examination chair. As examples, ophthalmic instruments such as slit lamps, indirect ophthalmometer and vision tester must be placed in front of a patient during eye examination procedures while the patient is seated in an examination chair. These instruments are typically placed on a movable table or on movable instrument support arms mounted adjacent the patient. Instrument support arms are generally attached to support poles forming part of an instrument stand. In some systems, two arms may be used with one arm supporting lighter weight instruments and the other arm supporting heavier weight instruments. Heavier weight instrumentation may also be supported on the movable tables mentioned above.
Support mechanisms that have taken the form of arms which move with multiple degrees of freedom. A typical support mechanism may, for example, rotate about the support pole and move up and down along the support pole. The mechanism may also have a first arm which adjusts vertically using a pivotal motion and have a second arm at an outer end which is pivotally connected to the first arm. Additional arms or support structure may be connected to the arms.
Each of the above described movements should be lockable such that a practician may set the mechanism and, therefore, the attached instrumentation in the desired location relative to the patient. Certain instrument arms are not lockable, however, this is not desirable in many situations. Most arms in the past have required at least two separate lock mechanisms and two separate manually operated levers or knobs to lock and unlock the various pivot connections of the mechanism. This makes locking and unlocking the mechanism cumbersome and often difficult for the practician. One known type of instrument support mechanism does include a single lever for locking and unlocking the three main pivoting movements described above. However, this lever must be rotated generally in a direction perpendicular to the mechanism. Therefore, the practician must use two hands to hold the mechanism against rotation about the support pole while rotating the lever to lock the mechanism in place. The same holds true when unlocking the mechanism. Also, the levers and knobs as previously located on such mechanisms may not be easily accessed or actuated by the practician.
For the reasons stated above as well as other reasons, it would be desirable to provide an adjustable medical instrument support mechanism, and especially a mechanism suitable for use in the ophthalmic area, in which a simplified and easily actuated locking mechanism is used and includes a single lever which may be actuated in a simple motion to either lock or unlock various pivot connections of the support mechanism.